Solar panel rack

ABSTRACT

A solar panel rack may comprise one or more sheet metal brackets configured to attach solar panels to the solar panel rack. The sheet metal brackets may include clinching tabs configured to be clinched to features on the solar panels to attach the solar panels to the solar panel rack. The sheet metal brackets may further include protrusions configured to facilitate electrical contact between the brackets and the solar panels when the clinching tabs are clinched to features on the solar panels. The sheet metal brackets may additionally or alternatively include positioning tabs configured to contact features on the solar panels to position the solar panels in desired locations on the solar panel rack.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of International Patent ApplicationPCT/US2014/042296 titled “Solar Panel Rack” and filed Jun. 13, 2014,which claims benefit of priority to U.S. Provisional Patent ApplicationNo. 61/842,516 titled “Solar Panel Rack” and filed Jul. 3, 2013, each ofwhich is incorporated by reference herein in its entirety.

FIELD OF THE INVENTION

The invention relates generally to the collection of solar energy, andmore particularly to solar panel mounting racks and their components.

BACKGROUND

Ground-mounted photovoltaic solar panels are conventionally supported onsolar panel mounting racks. Commercially available solar panel racks aretypically produced using aluminum extruded sections or steel roll formedsections in order to provide the structural strength required towithstand loads associated with outside conditions such as wind andsnow.

SUMMARY

Solar panel racks, their components, and related methods by which thesolar panel racks may be manufactured, assembled, and used aredisclosed.

In one aspect, a solar panel rack comprises one or more sheet metalbrackets and an underlying support structure to which the sheet metalbrackets are attached. Each sheet metal bracket comprises one or moreupwardly pointing clinching tabs and one or more upwardly pointingprotrusions. The clinching tabs are configured to be clinched tofeatures on a solar panel or solar panel assembly to attach the solarpanel or solar panel assembly to the solar panel rack in a desiredlocation in a plane defined by the solar panel rack. The protrusions areconfigured to facilitate electrical contact between the brackets and thesolar panel or solar panel assembly when the features on the solar panelor solar panel assembly are clinched by the clinching tabs.

The features on the solar panel or solar panel assembly may besandwiched between the protrusions and the clinching tabs when theclinching tabs are clinched, for example.

The upwardly pointing protrusions may be configured to pierce aninsulating coating on the features on the solar panel or solar panelassembly when the features are clinched by the clinching tabs.Accordingly, the upwardly pointing protrusions may comprise sharp edges,sharp points, or a combination of sharp edges and sharp points. Theupwardly pointing protrusions may have a conical volcano shape, forexample.

Each sheet metal bracket may comprise one or more upwardly pointingpositioning tabs configured to contact features on the solar panel orsolar panel assembly to position the solar panel or solar panel assemblyin the desired location. The positioning tabs of each sheet metalbracket may be located, for example, in a square or rectangulararrangement in a central portion of a top panel of the sheet metalbracket and extend upward from the top panel. Each sheet metal bracketmay be configured to position and attach adjacent corners of, forexample, four solar panels or solar panel assemblies to the solar panelrack.

The electrical contact facilitated by the upwardly pointing protrusionsmay form part of an electrical path from the solar panel or solar panelassemblies through the one or more sheet metal brackets and theunderlying support structure to ground.

The underlying support structure may comprise, for example, two or morehollow sheet metal beams arranged side by side and in parallel with eachother to define a plane. The beams may be supported in any suitablemanner as described herein, for example. Each sheet metal bracket mayhave an inner cross-sectional shape substantially conforming to theouter cross-sectional shape of a corresponding hollow sheet metal beamto which it is attached.

Each sheet metal bracket may comprise one or more tabs configured toengage corresponding slots or other openings in the underlying supportstructure to attach the sheet metal bracket to the underlying supportstructure, and one or more downwardly pointing protrusions configured toflex a portion of the underlying support structure to provide an elasticrestoring force securing the tabs in the slots or other openings. If theunderlying support structure comprises hollow sheet metal beams to whichthe sheet metal brackets are attached, the one or more downwardlypointing protrusions on each sheet metal bracket may be configured toflex an upper panel of the hollow sheet metal beam to provide therestoring force securing the tabs in the slots or other openings.

Each sheet metal bracket may be formed by bending a sheet metal blankalong bend lines predefined in the sheet metal blank by bend-inducingfeatures.

In another aspect, a solar panel rack comprises one or more sheet metalbrackets and an underlying support structure to which the brackets areattached. Each sheet metal bracket comprises one or more upwardlypointing clinching tabs configured to be clinched to features on a solarpanel or solar panel assembly to attach the solar panel or solar panelassembly to the solar panel rack in a desired location in a planedefined by the solar panel rack, one or more tabs configured to engagecorresponding slots or other openings in the underlying supportstructure to attach the bracket to the underlying support structure, andone or more downwardly pointing protrusions configured to flex a portionof the underlying support structure to provide an elastic restoringforce securing the tabs in the slots or other openings.

The underlying support structure may comprise, for example, two or morehollow sheet metal beams arranged side by side and in parallel with eachother to define a plane, with each sheet metal bracket attached to acorresponding one of the hollow sheet metal beams. The beams may besupported in any suitable manner as described herein, for example. Theone or more downwardly pointing protrusions on each sheet metal bracketmay be configured to flex an upper panel of the hollow sheet metal beamto provide the restoring force securing the tabs in the slots or otheropenings.

Each sheet metal bracket may comprise one or more upwardly pointingpositioning tabs configured to contact features on the solar panel orsolar panel assembly to position the solar panel or solar panel assemblyin the desired location. The positioning tabs of each sheet metalbracket may be located, for example, in a square or rectangulararrangement in a central portion of a top panel of the sheet metalbracket and extend upward from the top panel. Each sheet metal bracketmay be configured to position and attach adjacent corners of, forexample, four solar panels or solar panel assemblies to the solar panelrack.

If the underlying support structure comprises hollow sheet metal beamsto which the sheet metal brackets are attached, each sheet metal bracketmay have an inner cross-sectional shape substantially conforming to theouter cross-sectional shape of the hollow sheet metal beam to which itis attached.

Each sheet metal bracket may be formed by bending a sheet metal blankalong bend lines predefined in the sheet metal blank by bend-inducingfeatures.

Solar panel racks, their components, and related manufacturing andassembly methods disclosed herein may advantageously reduce material,manufacturing and installation costs for solar panel systems. This mayresult from a reduced amount of material used in the solar panel rackdesign, the use of cost-effective manufacturing methods, reducedshipping costs of solar panel rack components, which may be shipped toan installation site as substantially flat sheet metal blanks prior tobending to form the components, reduced storage space required for thecomponents, and reduced labor requirements for installing the solarracks and/or an increased rate of installation.

These and other embodiments, features and advantages of the presentinvention will become more apparent to those skilled in the art whentaken with reference to the following more detailed description of theinvention in conjunction with the accompanying drawings that are firstbriefly described.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1C show several views of a portion of an example solar panelrack with solar panels mounted on the rack (FIGS. 1A, 1B) and withoutsolar panels mounted on the rack (FIG. 1C).

FIGS. 2A-2B show a transverse support in an example solar panel rack(FIG. 2A) and an expanded view (FIG. 2B) of a notch in the transversesupport configured to receive and attach to a beam bracket that isconfigured to attach a longitudinal beam to the transverse support.

FIGS. 3A-3C show beam brackets attached to and positioned in notches ina transverse support (FIG. 3A), an expanded view of a beam bracketpositioned in a notch with its upper flanges open to receive alongitudinal beam (FIG. 3C), and an expanded view of a bracketpositioned in a notch with the bracket's upper flanges closed (FIG. 3B).

FIGS. 4A-4C show longitudinal beams positioned in beam brackets attachedto a transverse support, with the upper flanges of the beam bracketsopen (FIG. 4A) and closed (FIG. 4B, 4C) to secure the longitudinal beamsto the transverse support.

FIGS. 5A-5D show several views of a beam bracket configured to attachlongitudinal beams to transverse support structures in the example solarpanel rack.

FIG. 6A shows a sheet metal blank that may be folded to form a hollowlongitudinal beam for the example solar panel rack, FIG. 6B shows anexpanded view of a portion of the blank of 6A, FIGS. 6C-6H show severalviews of the longitudinal beam at different stages of folding, FIG. 6Ishows an expanded view of a sheet metal blank as in 6A comprisingbend-inducing features formed with a lance, and FIG. 6J shows anexpanded view of a sheet metal blank as in 6A comprising bend-inducingfeatures formed by laser-cutting.

FIGS. 7A-7G show several views of a collapsible and expandable internalsplice and its use in coupling two hollow beam sections together to forma longer hollow beam.

FIGS. 8A and 8B show a longitudinal beam end cap (FIG. 8B) and threesuch end caps at the ends of longitudinal beams in a portion of a solarpanel rack (FIG. 8A).

FIGS. 9A and 9B show perspective and side views, respectively, of apanel bracket configured to attach the corners of four neighboring solarpanels to a longitudinal beam in the example solar panel rack, FIG. 9Cshows a panel bracket attached to a longitudinal beam, and FIGS. 9D-9Gshow successive stages of attaching four neighboring solar panels to theexample solar panel rack using the panel brackets.

FIGS. 10A-10C illustrate a clinching process by which two neighboringsolar panels may be simultaneously secured to the example solar panelrack by the panel bracket of FIGS. 9A-9G.

FIGS. 11A and 11B show perspective and side views, respectively, ofanother variation of a panel bracket configured to attach the corners offour neighboring solar panels to a longitudinal beam in the examplesolar rack.

FIGS. 12A and 12B show close up views of the panel bracket of FIGS. 11Aand 11B, illustrating two variations of a protrusion that may be formedon a panel bracket to facilitate electrical contact between the panelbracket and a solar panel.

FIGS. 13A and 13B show two perspective views illustrating frame portionsof solar panels in place on the panel bracket of FIGS. 11A and 11B withthe panel bracket clinching tabs not clinched, FIG. 13C shows acorresponding side view of the solar panels in place on the panelbracket with the clinching tabs not clinched, and FIG. 13D shows thesame side view as FIG. 13C but with the panel bracket clinching tabsclinched to secure the solar panel frame portions.

FIG. 14A shows a top perspective view of solar panels in place on thepanel bracket of FIGS. 11A and 11B with the panel bracket clinching tabsclinched to secure the solar panel frame portions, FIG. 14B shows across-sectional view identified in FIG. 14A and a close-up of thatcross-sectional view, and FIG. 14C shows a related close-up view ofanother cross-section of the same assembly of solar panels on a panelbracket.

DETAILED DESCRIPTION

The following detailed description should be read with reference to thedrawings, in which identical reference numbers refer to like elementsthroughout the different figures. The drawings, which are notnecessarily to scale, depict selective embodiments and are not intendedto limit the scope of the invention. The detailed descriptionillustrates by way of example, not by way of limitation, the principlesof the invention. This description will clearly enable one skilled inthe art to make and use the invention, and describes severalembodiments, adaptations, variations, alternatives and uses of theinvention, including what is presently believed to be the best mode ofcarrying out the invention.

As used in this specification and the appended claims, the singularforms “a,” “an,” and “the” include plural referents unless the contextclearly indicates otherwise. Also, the term “parallel” is intended tomean “parallel or substantially parallel” and to encompass minordeviations from parallel geometries rather than to require that anyparallel arrangements described herein be exactly parallel. Similarly,the term “perpendicular” is intended to mean “perpendicular orsubstantially perpendicular” and to encompass minor deviations fromperpendicular geometries rather than to require that any perpendiculararrangements described herein be exactly perpendicular.

This specification discloses solar panel mounting racks, theircomponents, and related methods by which the solar panel racks may bemanufactured, assembled, and used. As illustrated in the variousfigures, the disclosed solar panel racks may be used, for example, in aground-mounted configuration to support photovoltaic panels in fixedpositions to collect and convert solar radiation to electricity. Otherconfigurations and applications for the disclosed solar racks will alsobe described below.

Various components of the disclosed solar panel racks including, forexample, the hollow beams, beam brackets, internal expandable beamsplices, and solar panel brackets further described below, may beadvantageously used in other structures unrelated to solar panels or tothe collection of solar energy. The discussion of these components inrelation to their roles in the disclosed solar panel rack is notintended to limit the scope of their potential use.

Referring now to FIGS. 1A-1C, an example solar panel rack 100 comprisesa vertical support 105, a transverse support 110 attached to an upperportion of the vertical support, and three hollow beams 115 supported bytransverse support 110. Hollow beams 115 are arranged in parallelorientations, with their upper surfaces defining a plane in which solarpanels are to be supported. In the illustrated example, hollow beams 115are secured in notches 117 (FIG. 2A) in transverse support 110 by beambrackets 120. Panel brackets 125, attached to hollow beams 115, areconfigured to attach solar panels 130 to the upper surfaces of beams115.

Although the illustrated solar panel rack comprises three parallelhollow beams, more generally the solar panel rack comprises two or moreparallel hollow beams arranged to define a plane in which solar panelsare to be supported. Transverse support 110 and hollow beams 115 may beconfigured so that the plane in which the solar panels are supported istilted with respect to vertical, rather than oriented horizontally. Thetilt angle may be selected to allow the solar panels to better collectsolar energy. (In this specification, “vertical” indicates the directionopposite to the force of the Earth's gravity). For example, and asillustrated, vertically oriented substantially identical notches 117 inthe upper edge of transverse support 110 may be located to secure thebeams 115 at progressively varying heights so that the beams can definea plane having a desired tilt angle. Further, beams 115 may havenon-rectangular cross-sections (FIG. 6D) such that flat upper surfacesof the hollow beams are angled with respect to the vertical to definethe desired tilted plane. The upper edge of transverse support 110 maybe angled substantially parallel to the intended plane of the solarpanels, as illustrated, to provide clearance for the solar panels.

The portion of the example solar panel rack illustrated in FIGS. 1A-1Cmay be repeated as a unit to form a linearly extending, modular, solarpanel rack of desired length. In such linearly extending solar panelracks, corresponding hollow beams in adjacent repeating units may bearranged collinearly and spliced together with internal expandablesplices 135 as further described below. Two or more such linearlyextending solar panel racks may be arranged in parallel and side-by-sideto support two or more corresponding spaced-apart rows of solar panelsin an array of solar panels.

Individual solar panels to be supported by solar panel rack 100 mayhave, for example, a width of about 0.9 meters to about 1.3 meters and alength of about 1.5 meters to about 2.5 meters. More generally, suchsolar panels may have any suitable dimensions. The width of the solarpanel rack may be selected, for example, to be approximately equal to aninteger multiple of the solar panel width or length, or to a sum ofinteger multiples of the solar panel width and the solar panel length.As illustrated, for example, the solar panel rack may have a widthapproximately equal to twice the length of a solar panel. Moregenerally, solar panel rack 100 may have any suitable width. Solarpanels may be grouped into assemblies of solar panels prior to beinginstalled on solar panel rack 100. Such a solar panel assembly may behandled and installed similarly to as described herein for an individualsolar panel.

Beams 115 may have lengths of, for example, about 3 meters to about 8meters. The beam lengths may be selected, for example, to beapproximately equal to an integer multiple of the solar panel width orlength, or to a sum of integer multiples of the solar panel width andthe solar panel length. Two or more beams 115 may be spliced together asnoted above to form part of a solar panel rack having an overall lengthof, for example, about 24 meters to about 96 meters supported bymultiple transverse supports 110 and corresponding vertical supports105. Though FIGS. 1A-1C show a single transverse support used to supportone beam-length of solar panel, in other variations two or moretransverse supports 110, with corresponding vertical supports 105, maybe spaced along a beam-length of the solar panel. For example, inlinearly extending solar panel racks comprising beams collinearlyspliced together to lengthen the rack, there may be one, two, or morethan two transverse supports spaced along the solar panel rack betweenbeam splices or between the end of the solar panel rack and a beamsplice.

Although the example solar panel rack of FIGS. 1A-1C is shown comprisinga vertical support, a transverse support, hollow beams, brackets forattaching the hollow beams to the transverse support, and brackets forattaching the solar panels to the hollow beams, variations of the solarpanel rack may lack any one of these components, or lack any combinationof these components, and may comprise additional components not shown.

Transverse supports, hollow beams, and brackets used in the solar panelracks disclosed in this specification may advantageously be formed bybending sheet metal blanks into the desired shape. Flat sheet metalblanks from which these components are formed may be patterned, forexample, with slits, grooves, score lines, obround holes, or similarbend-inducing features that define predetermined bend lines along whichthe sheet metal blanks may be bent to form the desired structures.

Such bend-inducing features may include, for example, slits, grooves,displacements, and related bend-inducing features as disclosed in U.S.Pat. No. 6,877,349, U.S. Pat. No. 7,152,449, U.S. Pat. No. 7,152,450,U.S. Pat. No. 7,350,390, and US Patent Application Publication No.2010/0122,563, all of which references are incorporated herein byreference in their entirety. A “displacement” as disclosed in thesereferences is a bend-inducing feature comprising a tongue of materialdefined in a sheet metal blank by a cut or sheared edge located on oradjacent the bend line, with the tongue displaced at least partially outof the plane of the sheet metal blank before the sheet metal blank isbent along that bend line. The use of bend-inducing features,particularly those disclosed in these references, may increase theprecision with which the sheet metal blanks may be bent into the desiredcomponents and reduce the force necessary to bend the blanks. Thebend-inducing features disclosed in the cited references may exhibitedge-to-face engagement, as described in the references, upon bending.Such edge-to-face engagement may contribute to the precision with whichbending may be accomplished and to the stiffness and strength of theresulting component.

Example flat sheet metal blanks from which hollow beams 115 may beformed in some variations are illustrated in FIGS. 6A-6J and describedbelow. For other components of solar panel rack 100 for which nocorresponding flat sheet metal blank with bend-inducing features isillustrated, the predetermined bend lines defined by bend inducingfeatures in such sheet metal blanks should be understood to be locatedat positions corresponding to the bends evident in the finishedstructures shown in the drawings.

In some variations, transverse supports, hollow beams, and/or bracketsused in the solar panel may be formed from sheet metal blanks withoutthe use of bend-inducing features to predefine the bend lines. In suchvariations, the sheet metal blanks may be bent into the desired shapeusing, for example, conventional press-brake, stamping press, orroll-forming technology.

Sheet metal blanks for the components of solar panel rack 100, includingbend-inducing features if used, may be formed using laser cutting,computer numerical controlled (CNC) metal punching, and/or metalstamping, for example. Such techniques allow for low cost manufacturingof the components.

The use of sheet metal components in solar panel rack 100 allows suchcomponents to be attached to each other using sheet metal screws orother sheet metal fasteners, rather than with double sidedbolt/washer/nut fastener assemblies which can be difficult and slow toinstall. The single sided installation process of driving a sheet metalscrew using, for example, a magnetic electric drive attachment may beadvantageous for both the reduced cost of the fasteners and theincreased ease and speed of installation. The use of sheet metalcomponents as described herein may also reduce the overall amount andweight of material used in the solar panel racks while maintainingdesired stiffness and strength. Nevertheless, as suitable, one or morecomponents not formed from bent sheet metal, such as cast, extruded, ormachined components, for example, may be substituted for the sheet metalcomponents otherwise described in this specification.

The individual components of the example solar panel rack 100 of FIGS.1A-1C are next described in further detail with respect to additionaldrawings.

Referring again to FIGS. 1A-1C, vertical support 105 may be, forexample, any conventional pile or post suitable for supporting solarpanel rack 100 and may be formed from any suitable material. Verticalsupport 105 may have a Σ (sigma) cross section, for example. AlthoughFIGS. 1A-1C show only one vertical support 105 attached to transversesupport 110, other variations of the solar panel rack may use two ormore such vertical supports spaced apart and attached to transversesupport 110. For ground-mounted configurations, vertical support 105 maybe, for example, driven into the ground, ballasted with respect to theground, screwed into the ground, or affixed to or upon the ground by anyother suitable means.

As illustrated in the various figures, transverse support 110 has asaddle shape selected to reduce the amount of material necessary toprovide sufficient strength and stiffness to support beams 115 and solarpanels 130. As noted above, notches 117 in the upper edge of transversesupport 110 are configured to receive brackets 120 and beams 115. Anyother suitable shape or configuration for transverse support 110 mayalso be used.

Transverse support 110 may be attached to vertical support 105 usingbolt/washer/nut assemblies or any other suitable fasteners or method.Attachment may be accomplished, for example, with suitable fastenerspassing through vertical slots in vertical support 105 and throughhorizontal slots in transverse support 110. Alternatively, attachmentmay be accomplished, for example, with suitable fasteners passingthrough horizontal slots in vertical support 105 and through verticalslots in transverse support 110. Such arrangements of vertical andhorizontal slots provide an adjustment that may be used to compensatefor imprecision in the placement of vertical support 105 with respect toother vertical supports in the solar panel rack.

Referring now to FIGS. 2A and 2B, in the illustrated example transversesupport 110 is formed from a flat sheet metal blank that is bent alongpredefined bend lines to form panel section 110 a, upper flange 110 b,and lower flanges 110 c. Upper flange 110 b and lower flanges 110 c arebent perpendicular to panel 110 a to impart stiffness to panel 110 a.The sheet metal blank for transverse support 110 is also bent alongpredefined bend lines to form flanges 110 d, which are orientedperpendicular to panel 110 a to form side walls to notches 117. Panel110 a includes one or more tabs 140 projecting into each notch 117.Variations including two or more tabs per notch, for example, may haveone or more tabs projecting into the notch from either side of thenotch. In variations having only one projecting tab per notch, the tabson the outer notches may preferably be located on the sides of thenotches interior to the solar panel rack, away from the edges of thesolar panel rack. Tabs 140 may be defined in the sheet metal blank bysheared or cut edges, and remain in the plane of panel 110 a, or atleast substantially parallel to the plane of panel 110 a, when flanges110 d are bent perpendicular to panel 110 a. As described below, tabs140 may be inserted into slots or other openings in brackets 120 totemporarily secure brackets 120 in notches 117 without the use offasteners. Although two tabs 140 are used for each notch 117 in theillustrated example, any other suitable number of tabs 140 may be usedper notch. Alternatively, flanges 110 d may comprise one or morepreformed slots or other openings into which one or more tabs onbrackets 120 may be inserted to temporarily secure brackets 120 innotches 117. In the illustrated example, the dimensions andcross-sectional shape of notches 117 in transverse support 110 areselected to conform to the shape of brackets 120 and to provide afriction fit for brackets 120.

The predefined bend lines in the sheet metal blank for transversesupport 110 may comprise any suitable bend-inducing features asdescribed herein, known in the art, or later developed. The sheet metalblank for transverse support 110 may be formed, for example, fromgalvanized steel sheet having a thickness, for example, of about 1.9millimeters. Any other suitable material and thickness may also be used.

Referring now to FIGS. 3A-3C, 4A-4C, 5A, and 5B, in the illustratedexample bracket 120 is formed from a flat sheet metal blank that is bentalong predefined bend lines to form bottom panel 120 a, side panels 120b, and upper flanges 120 c. Side panels 120 b are bent with respect tobottom panel 120 a to form a bracket shape conforming to the shape ofnotch 117 (Figure B) and to the cross-sectional shape of beams 115 (FIG.6D). Upper flanges 120 c may be bent to close (FIG. 3B) and to open(FIG. 3C) the upper end of bracket 120. Side panels 120 b comprise slots120 d configured and positioned to engage with corresponding tabs 140 onflanges 110 d of transverse support 110 when brackets 120 are properlypositioned in notches 117 in transverse support 110.

The predefined bend lines in the sheet metal blank for bracket 120 maycomprise any suitable bend-inducing features as described herein, knownin the art, or later developed. The sheet metal blank for bracket 120may be formed, for example, from galvanized steel sheet having athickness, for example, of about 1.9 millimeters. Any other suitablematerial and thickness may also be used.

Once bent into shape, brackets 120 are inserted into notches 117 andtemporarily secured in place by engaging tabs 140 on transverse support110 with slots 120 d on brackets 120. Beams 115 are positioned in placein brackets 120 (FIG. 4A), and then upper flanges 120 c of brackets 120are bent into their closed positions (FIGS. 4B, 4C) to capture beams 115within brackets 120. Sheet metal fasteners may then be driven throughpreformed holes 110 e in flanges 110 d of transverse support 110 andthrough correspondingly aligned preformed holes 120 e in bracket 120into beams 115 to secure the brackets 120 and the beams 115 totransverse support 110. Additional sheet metal fasteners may be driventhrough preformed holes 120 f in upper flanges 120 c of brackets 120into beams 115 to further secure beams 115 to brackets 120. The sheetmetal fasteners attaching transverse support 110 and brackets 120 tobeams 115 may preferably be self-drilling fasteners that drill into andengage beams 115. The use of such self-drilling fasteners allows theposition of transverse supports 110 and vertical supports 105 alongbeams 115 to be selected at the installation site to adapt to localcircumstances, such as to rocks or other objects that might interferewith or constrain the positioning of vertical supports 105.Alternatively, the sheet metal fasteners attaching transverse support110 and brackets 120 to beams 115 may engage preformed holes in beams115. (Preformed holes referred to here and elsewhere in thespecification are formed in corresponding sheet metal blanks prior tobending of the sheet metal blanks to form the desired components).

The ability to temporarily position brackets 120 in transverse support110 without the use of fasteners, by means of the tab and slotarrangement just described, allows beams 115 to be positioned in thesolar panel rack prior to final attachment of the brackets using sheetmetal screws. A benefit of this arrangement is that installers need nothandle multiple components at one time, nor are fasteners handled atthat same time as well. De-coupling complex installation steps mayfacilitate faster installation as well as lower the labor costs andskill required.

The inventors have recognized that hollow sheet metal beams such asbeams 115 may buckle under load if they are supported by hard narrowedges that concentrate the reaction force from the supporting structureonto a narrow region of the hollow beam. Brackets 120 increase the loadcapacity of beams 115 by distributing the force from the load on beams115 along the length of the brackets. This helps to prevent bucklingthat might otherwise occur if the force from the load on beams 115 wereconcentrated at the hard upper edge of transverse support 110. Further,each bracket 120 may be shaped so that its stiffness progressively andgradually decreases with distance in both directions away fromtransverse support 110 along its beam 115. (The stiffest portion of abracket 120 is the central region of the bracket that is in contact withand supported by transverse support 110). Because of this progressivedecrease in stiffness, the ends of brackets 120 away from transversesupport 110 displace significantly downward under load and consequentlydo not themselves present hard edges that promote buckling of beams 115.

Referring now to FIGS. 5A-5D, in the illustrated example brackets 120have stiffness that progressively decreases with distance fromtransverse support 110 because bottom panels 120 a, side panels 120 b,and upper flanges 120 c all have widths that progressively decrease froma wide central portion to narrower portions at the panel's outer edges,farthest from transverse support 110. That is, material has been removedfrom central regions of the panels away from the transverse support 110,with the regions from which material has been removed having widths thatincrease with distance from transverse support 110. This configurationenhances load capacity in all four primary load directions—verticallyupward, downward, and in both lateral directions. Any other suitableshape or configuration of brackets 120 may also be used to provide theprogressive decrease in stiffness just described. For example, theprogressive decrease in stiffness of the bracket may alternatively beprovided by progressive changes in width of only some of its panels,although such a configuration may not enhance load capacity indirections perpendicular to the panels that do not exhibit progressivelyreduced stiffness. Further, although the illustrated brackets 120 aresymmetric about transverse support 110 and about hollow beams 115,neither of these symmetries is required.

The use of brackets 120 exhibiting progressive decreases in stiffness asdescribed in this specification may advantageously increase the capacityof a solar panel rack to handle high loads caused by wind or snow, forexample. Brackets 120 are not required to exhibit such progressivedecreases in stiffness, however. For example, the bottom panels, sidepanels, and upper flanges of bracket 120 may be formed as completepanels without material removed from central regions as described above,and thus fully wrap the bottom and side panels of a beam 115 for thelength of the bracket 120. In such variations, the bracket 120 may havea length of, for example, about 1/10 of the beam length to about ⅓ ofthe beam length. Brackets of sufficient length, for example greater thanor equal to about ⅓ of the beam length, may advantageously spread theload on the beam along the beam to significantly reduce a stress spikethat may otherwise occur in the beam. Also in such variations, thebracket 120 may have a length of, for example, about 2 times the beamheight (or about 2 times the largest cross-sectional dimensionperpendicular to the beam length) to about 7 times the beam height (orabout 7 times the largest cross-sectional dimension perpendicular to thebeam length). Brackets of sufficient length, for example greater than orequal to about 5 times the beam height (or about 5 times the largestcross-sectional dimension perpendicular to the beam length), mayadvantageously spread the load on the beam along the beam tosignificantly reduce a stress spike that may otherwise occur in thebeam. In such variations (in which the bottom panels, side panels, andupper flanges of bracket 120 may be formed as complete panels withoutmaterial removed from central regions), bracket 120 may be formed, forexample, from galvanized steel sheet having a thickness of, for example,about 1.5 millimeters. Any other suitable material and thickness mayalso be used.

Referring now to FIGS. 6A-6J, in the illustrated example each beam 115is formed from a flat sheet metal blank 145 (FIGS. 6A-6C, 6I, 6J) thatis bent along predefined bend lines to form a beam 115 having aquadrilateral cross-section comprising bottom panel 150 a, side panel150 b, top panel 150 c, side panel 150 d, and closure flanges 150 e and150 f (FIGS. 6D-6H). Upon bending of sheet metal blank 145 into thedesired cross-sectional shape, flange 150 e and bottom panel 150 aoverlap, and flange 150 f and side panel 150 d overlap. Flanges 150 eand 150 f may then be fastened to the panels with which they overlapusing sheet metal fasteners passing through preformed holes, forexample, or by any other suitable method, to secure beam 115 in itsclosed configuration.

In the illustrated example, beam 115 is secured in its closedconfiguration using tabs and slots preformed in sheet metal blank 145.As illustrated, flange 150 f comprises a repeating pattern of tabs 155and flange 150 e comprises a corresponding repeating pattern of slots160 formed along the bend line between flange 150 e and side panel 150d. When sheet metal blank 145 is bent to form the desiredcross-sectional shape, tabs 155 remain in the plane of bottom panel 150a, or at least substantially parallel to the plane of bottom panel 150a, and thus protrude from flange 150 f. These protruding tabs 155 may beinserted through corresponding slots 160 (FIGS. 6E, 6G) and then bent tolie flat alongside panel 150 d (FIGS. 6F, 6H) to secure bottom panel 150a to side panel 150 d.

Preformed tabs 155 may be formed as tongues of material defined by a cutor sheared edge, with the tongues displaced at least partially out of,but still substantially parallel to, the plane of sheet metal blank 145prior to bending (FIGS. 6B, 6C, 6I). This may be accomplished usingsheet metal lancing methods, for example. Alternatively, preformed tabs155 may be formed as tongues of material defined by a laser-cut edge,with the tongues remaining within the plane of sheet metal blank 145prior to bending of the blank (FIG. 6J).

The use of integrated tabs 155 and slots 160 as just described allowssheet metal blank 145 to be bent into shape and joined to itself to forma beam 115 without the use of welding, fasteners, or other means ofjoinery. Such other means of joinery may be used in addition to suchtabs and slots if desired, however.

As noted above, beams 115 as illustrated have quadrilateralcross-sectional shapes. Such quadrilateral cross-sectional shapes mayallow beams 115 to provide optimal load capacity in all four primaryload directions—vertically upward, downward, and in both lateraldirections. (Lateral loads may be caused by wind, for example). Othercross-sectional beam shapes may also be used, however, if suitable.

Sheet metal blank 145 may comprise preformed holes or slots into whichtabs on panel brackets 125 are to be inserted, as further describedbelow. Alternatively, sheet metal blank 145 may comprise predefinedfeatures that, upon folding of the blank, form tabs on beam 115 that maybe inserted into preformed holes or slots on panel brackets 125. Suchtab and slot arrangements predefine the locations of panel brackets 125,and thus of solar panels 130, with respect to the beams in solar panelrack 100. This promotes installation speed and prevents errors thatmight otherwise occur in positioning panel brackets 125 and solar panels130 on solar panel rack 100.

The predefined bend lines in sheet metal blank 145 may comprise anysuitable bend-inducing features as described herein, known in the art,or later developed. Sheet metal blank 145 may be formed, for example,from galvanized steel sheet having a thickness, for example, of about0.9 millimeters or about 1.2 millimeters. Any other suitable materialand thickness may also be used.

The inventors have determined that the resistance of beams 115 tobuckling under stress may be promoted by particular configurations ofbend-inducing features used to define the bend lines in sheet metalblank 145. The inventors have recognized that a beam's resistance tobuckling increases as the length of the individual bend-inducingfeatures defining the bend lines is shortened. As further explainedbelow, the inventors have also recognized that there is typically apractical lower limit to the length of a bend-inducing feature, withthat lower limit related to the composition and the thickness of thesheet of material. These opposing trends result in optimal ranges forthe lengths of bend-inducing features used to define bend lines in sheetmetal blanks to be formed into hollow beams such as beams 115.

Referring now to FIG. 6I, bend lines in sheet metal blank 145 may bedefined by rows of spaced-apart displacements 165, each of which has alength along the bend line identified as “A” in the drawing. Eachdisplacement 165 comprises a cut or sheared edge 165 a of a tongue ofmaterial 165 b. Severed edge 165 a is at least partially curved, andtypically has ends that diverge away from the bend line. Tongue 165 b isdisplaced at least partially out of the plane of sheet metal blank 145at the time displacement 165 is formed, prior to bending of the blank,but remains attached to and substantially parallel to the blank. Lateralends of the severed edge 165 a, and thus of tongue 165 b, have a radiusof curvature R (not shown).

If the radius of curvature R of the ends of the displacements is toosmall, the sheet metal blank may crack at the ends of the displacementsupon folding of the blank. The inventors have determined that the radiusof curvature R of the ends of the displacement 165 in sheet metal blank145 should be selected to be R_(min), or larger than but approximatelyR_(min), where R_(min) is the minimum radius of curvature that may beused without initiating cracking at the ends of the displacements uponfolding the sheet metal blank to form the beam. The practical lowerlimit to the length of a displacement 165 is approximately 2R_(min).Typically, larger sheet thicknesses require a larger radius of curvatureR to prevent cracking. More brittle materials also require a largerradius of curvature. The inventors have also found that resistance tobeam buckling decreases with increasing displacement length “A”, andthat resistance to beam buckling has typically decreased significantlyfor displacements having a length “A” greater than approximately6R_(min). Thus inventors have determined that bend inducingdisplacements to be used in forming a hollow sheet metal beam 115preferably have a length “A” that satisfies the relationshipA≦˜6R_(min), or more preferably satisfies the relationship˜2R_(min)≦A≦˜6R_(min).

Referring now to FIG. 6J, bend lines in sheet metal blank 145 mayalternatively be defined by rows of spaced-apart “smile shaped” slits170, with adjacent slits on alternating sides of the bend line. Slits170, which penetrate through sheet metal blank 145, define tongues 170 athat remain in the plane of sheet metal blank 145 prior to bending. Asillustrated, lateral ends of the slits 170 diverge away from the bendline. Each of slits 170 has a length along the bend line identified as“A” in the drawing. The inventors have determined that suchbend-inducing smile-shaped slits to be used in forming a hollow sheetmetal beam 115 preferably have a length “A” that falls within the samerange as that for the use of displacements as discussed above. That is,the length A of the smile shaped slits should satisfies the relationshipA≦˜6R_(min), or more preferably satisfies the relationship˜2R_(min)≦A≦˜6R_(min), where R_(min) is the minimum radius of curvaturethat may be used for displacements (as discussed above) withoutinitiating cracking at the ends of the displacements upon folding thesheet metal blank to form the beam.

Beams 115 may be formed, for example, from galvanized steel sheetshaving a thickness of about 0.9 millimeters or about 1.2 millimeters andbend lines defined by displacements or smile-shaped slits, as describedabove, having lengths of about 9 millimeters or less.

As noted above, two beams 115 may be arranged collinearly in a solarpanel rack 100 and spliced together using internal splices 135.Referring now to FIGS. 7A-7G, in the illustrated example a splice 135may be formed from a sheet metal blank that is bent along predefinedbend lines to form a short hollow beam section having a quadrilateralcross-section comprising bottom panel 175 a, side panel 175 b, top panel175 c, side panel 175 d, and closure flange 175 e. Panels 175 a, 175 b,175 c, and 175 d correspond in position, shape, and orientation topanels in beam 115. Closure flange 175 e may be bent into contact withand optionally fastened to side wall 175 b. Outer cross-sectionaldimensions of splice 135 approximately match the internalcross-sectional dimensions of beams 115, to allow a tight fit betweenthe splice and a beam as further described below. Splices 135 may have alength, for example, of about 0.25 meters to about 1.0 meters.

Splice 135, and the sheet metal blank from which it is formed, alsocomprise two or more additional predefined bend lines which may be bentwith low force to partially collapse splice 135. In the illustratedexample, splice 135 comprises predefined low-force bend lines 180 and185 running parallel to the long axis of the splice in side panels 175 band 175 d, respectively, which are positioned on opposite sides ofsplice 135. These low force bend lines allow splice 135 to be partiallycollapsed (FIG. 7C), and then inserted into an end of a hollow beam 115(FIGS. 7D and 7E). Typically, splice 135 is inserted into beam 115 to adepth of about one half the length of splice 135, as shown in FIG. 7A,for example. A second hollow beam 115 may then be slid over theremaining exposed half length of splice 135.

Splice 135, in its collapsed configuration, may thus be positionedentirely within two adjacent and collinear hollow beams 115. Sheet metalfasteners may then be inserted through preformed clearance holes 190(FIG. 7E) in each of the two hollow beams 115 to engage preformed holesin side panels 175 b and 175 d of splice 135 to pull splice 135 into itsexpanded configuration (FIGS. 7F, 7G). The two hollow beams 115 arethereby coupled to each other through their attachment to splice 135.(Note that in order to show a perspective view of an expanded splice 135in position inside a hollow beam 115, FIG. 7G shows only one of the twohollow beams 115 typically coupled to such a splice).

Further, because the outer cross-sectional dimensions of splice 135approximately match the internal cross-sectional dimensions of beams115, when splice 135 is expanded within beams 115 the splice's top,bottom, and side panels fit tightly against the corresponding panels ofthe beams 115. This provides strength and stiffness that allows splice135 and its attached beams 115 to handle multidirectional loads. Inaddition, splice 135 does not interfere with the positions of othercomponents of solar rack 100 that are attached to beams 115, such aspanel brackets 125 for example, because splice 135 in its finalconfiguration is located within beams 115.

Hollow beams 115 may optionally comprise preformed holes 195 (FIG. 7E)through which a screwdriver or other object may be temporarily insertedas a stop to control the depth to which a splice 135 is inserted into ahollow beam 115.

The predefined bend lines in the sheet metal blank for splice 135 maycomprise any suitable bend-inducing features as described herein, knownin the art, or later developed. The sheet metal blank for splice 135 maybe formed, for example, from galvanized steel sheet having a thickness,for example, of about 0.9 millimeters to about 1.2 millimeters. Anyother suitable material and thickness may also be used.

Referring now to FIGS. 8A and 8B, solar panel rack 100 may also compriseend caps 200 inserted into and closing the ends of hollow beams 115 atthe ends of solar panel rack 100. An end cap 200 may be formed from asheet metal blank bent along predefined bend lines to form end panel 205a and side flanges 205 b. End panel 205 a may be inserted into the endof a hollow beam 115, with tabs 205 c on end panel 205 a engagingcorresponding preformed slots in the hollow beam 115 to retain the endcap in the hollow beam. Alternatively, hollow beam 115 may comprise tabsthat are inserted into preformed slots in side flanges 205 b to retainthe end cap in the hollow beam. In either case, side flanges 205 b mayextend outward from and collinearly with hollow beam 115 to support anoverhanging portion of a panel bracket 125 positioned at the end ofhollow beam 115 (FIG. 8A).

The predefined bend lines in the sheet metal blank for end cap 200 maycomprise any suitable bend-inducing features as described herein, knownin the art, or later developed. The sheet metal blank for end cap 200may be formed, for example, from galvanized steel sheet having athickness, for example, of about 0.5 millimeters to about 1.2millimeters. Any other suitable material and thickness may also be used.

Referring now to FIGS. 9A-9G, in the illustrated example a panel bracket125 is formed from a sheet metal blank that is bent along predefinedbend lines to form a top panel 210 a, side panels 210 b bent downwardfrom top panel 210 a so that top panel 210 a and side panels 210 btogether conform to the cross-sectional shape of a hollow beam 115, fourpositioning tabs 210 c located in a square or rectangular arrangement ina central portion of top panel 210 a and extending upward from panel 210a, four solar panel clinching tabs 210 d extending upward from panel 210a and each positioned adjacent to a positioning tab 210 c, and flanges210 e bent perpendicularly outward from side panels 210 b to stiffenside panels 210 b.

Side panels 210 b of panel brackets 125 comprise tabs 210 f that may beinserted into preformed slots in a hollow beam 115 to position the panelbrackets at desired locations on the hollow beam (FIGS. 9B, 9C). Asfurther described below, panel brackets 125 are configured to properlyposition and attach the corners of up to four solar panels 130 to ahollow beam 115. This arrangement allows the preformed slots in hollowbeams 115 to predefine the positions of solar panels 130 on solar panelrack 100.

To position and attach solar panels 130 to solar panel rack 100, panelbrackets 125 are first positioned on hollow beams 115 using the tab andslot arrangement described above. Panel brackets 125 may then be furthersecured to the beams with sheet metal fasteners driven through preformedholes 215 in side panels 210 b into preformed holes in hollow beams 115.Solar panels 130 are then guided into position by contact between outeredges of solar panels 130 and positioning tabs 210 c, as well as bycontact between solar panels 130 and clinching tabs 210 d (FIGS. 9D-9G).

Clinching tabs 210 d are configured to be clinched aroundindustry-standard features 220 on solar panels 130 to attach the solarpanels to panel brackets 125 and thus to hollow beams 115 (FIGS. 10A,10C). In the illustrated example, a pair of clinching tabs 210 d locatedon the same side of a hollow beam 115 may be simultaneously clinchedaround features 220 on adjacent solar panels 130 using a conventionalclinching tool shown in FIG. 10B in its open 225A and clinched 225Bconfigurations. This simultaneous clinching method increases the speedof installation. Optionally, solar panels 130 may be further secured topanel brackets 125 with fasteners passing through preformed holes inpanel bracket 125. Features 220 may be flanges on an outer frame ofsolar panel 130, for example.

FIGS. 11A-14C show another variation of panel bracket 125. Thisvariation of the panel bracket is also configured to properly positionand attach the corners of up to four solar panels 130 to a hollow beam115, with slots in hollow beams 115 predefining the positions of solarpanels 130 on solar panel rack 100. Referring now to FIGS. 11A and 11B,the illustrated panel bracket 125 is formed from a sheet that is bentalong predefined bend lines to form a top panel 230 a, end panels 230 bbent downward from top panel 230 a, side panels 230 c also bent downwardfrom top panel 230 a, top beam attachment panels 230 d bent outward fromside panels 230 c into an orientation parallel to top panel 230 a, andside beam attachment panels 230 e bent downward from top beam panels 230d so that a top beam panel 230 d and its side beam panels 230 e togetherconform to the cross-sectional shape of a hollow beam 115. End panels230 b may be bent into position prior to side panels 230 c, provide ahard stop defining the final orientation of side panels 230 c, and braceside panels 230 c in their final position. Side beam attachment panels230 e comprises (e.g., hook-like) tabs 230 h that may be inserted intopreformed slots in a hollow beam 115 to position the panel brackets atdesired locations on the hollow beam.

The sheet from which panel bracket 125 is formed is also bent alongpredefined bend lines to form six positioning tabs 230 f located in asquare or rectangular arrangement in a central portion of top panel 230a and extending upward from panel 230 a, and four solar panel clinchingtabs 230 g also extending upward from panel 230 a. As further explainedbelow, these positioning and clinching tabs function similarly topositioning tabs 210 c and clinching tabs 210 d of the panel bracket ofFIGS. 9A-9G.

In addition to the features just described, panel brackets 125 of FIGS.11A-14C include upward pointing protrusions 235, which are configured tofacilitate electrical contact between the panel bracket and a metalframe or other conducting feature of a solar panel attached to the solarpanel rack by the panel bracket. The electrical contact facilitated byprotrusions 235 may form part of an electrical path from the solarpanel, through the solar panel rack, to electrical ground. Such a groundpath may run, for example, from a metal frame of the solar panel throughpanel bracket 125 to a beam 115, and then from the beam 115 through abeam bracket 120 to saddle 110, and then from saddle 110 throughvertical support 105 to ground.

The metal frame or other conducting component of the solar panelsintended to form part of such a ground path may have an insulating orpartially insulating coating that reduces its conductivity. For example,anodized aluminum solar panel frames and galvanized steel solar panelframes will likely have such insulating or partially insulatingcoatings. Protrusions 235 may be configured to pierce such a coating toincrease the conductivity of the contact between the panel bracket 125and the solar panel. This may be accomplished, for example, with aprotrusion geometry that provides strength under compression incombination with one or more sharp edges positioned to pierce theinsulating coating when clinching tabs 230 g are clinched around thesolar panel frame and squeeze the panel frame between protrusions 235and clinching tabs 230 g.

Any suitable geometry for protrusions 235 may be used. Referring toFIGS. 11A and 12A, protrusions 235 may have, for example, the shape of aconical volcano with a sharp and substantially continuous rim 235 a. Inan alternative example shown in FIG. 12B, protrusions 235 have the shapeof a conical volcano with a ruptured rim exhibiting sharp points 235 b.

Protrusions 235 may be formed integrally with panel bracket 125. Forexample, the protrusions illustrated in FIGS. 12A and 12B may be formedin the panel bracket sheet metal blank with a punch and a die.Alternatively, protrusions 235 may be formed separately from panelbracket 125 and then attached to panel bracket 125 by any suitablemethod.

Referring now to FIGS. 13A-13C, to attach one or more solar panels 130to a solar panel rack 100 using panel brackets 125 of FIGS. 11A and 11B,the panel brackets 125 are first positioned on hollow beams 115 usingthe tab and slot arrangement described above. Panel brackets 125 maythen be further secured to the beams with sheet metal fasteners driventhrough preformed holes 237 in side beam attachment panels 230 e. One,two, three, or four solar panels 130 are then guided into position bycontact between outer edges of solar panels 130 (e.g., solar panelframes) and positioning tabs 230 f, as well as by contact between solarpanels 130 and clinching tabs 230 g.

Referring now to FIGS. 13D-14C, clinching tabs 230 g are configured tobe clinched around industry-standard features (e.g., frames) on solarpanels 130 to attach the solar panels to panel brackets 125 and thus tohollow beams 115. In the illustrated example, a pair of clinching tabs230 g located on the same side of a hollow beam 115 may besimultaneously clinched around features on adjacent solar panels 130using a conventional clinching tool (e.g., as shown in FIG. 10B in itsopen 225A and clinched 225B configurations). Optionally, solar panels130 may be further secured to panel brackets 125 with fasteners passingthrough preformed holes in panel bracket 125.

The close-up cross-sectional view in FIG. 14B, taken along line A-A ofFIG. 14A, shows a flange on the frame of a solar panel 130 sandwichedbetween a protrusion 235 and a clinching tab 230 g, thus facilitatingelectrical contact between the panel bracket 125 and the solar panel 130through protrusion 235 as described above. FIG. 14C shows a relatedcross-sectional view, taken parallel to line A-A of FIG. 14A but furtheralong the panel bracket and away from protrusions 235. As the latterfigure shows, away from protrusions 235 the flange of the solar panelframe is bent downward past protrusions 235 to make direct contact withpanel bracket top panel 230 a and be sandwiched between top panel 230 aand clinching tab 230 g. Bent in this manner, the flange on the solarpanel frame typically exhibits a restoring force toward its originalflat configuration that tends to pull the flange tightly againstprotrusion 235, further enhancing electrical contact between the solarpanel and the panel bracket.

Referring again to FIGS. 11A and 11B, in these examples the beamattachment top panels 230 d include downward pointing protrusions 240.These protrusions are configured to elastically flex a top panel of thehollow beam to which the panel bracket is attached, so that the beamexerts a restoring force tending to pull tabs 230 h on beam attachmentside panels 230 e toward the top of the beam, thereby tightly securingthe tabs in position in the slots that they engage in the beam. In theillustrated examples, protrusions 240 are downward pointing dimplesintegrally formed in the sheet metal blank for panel bracket 125. Anyother suitable geometry for protrusions 240 may be used. Rather thanintegral with panel bracket 125, protrusions 240 may be separatelyformed and then attached to beam attachment top panels 230 d.

In variations including protrusions 240, a tight fit between beamattachment panels 230 d and 230 e and the beam and/or contact betweentabs 230 h and the beam may provide acceptable electrical contactbetween the panel bracket and the beam for a desired ground path.Alternatively, or in addition, suitable electrical contact may beprovided by fasteners engaging the beam through preformed holes 237 inpanels 230 e, or in any other suitable manner.

Protrusions 235 and protrusions 240 may be advantageous but are notrequired. Further, protrusions 235 may be used without protrusions 240,and protrusions 240 may be used without protrusions 235. Either or bothprotrusions 235 and protrusions 240 may be used in variations of thepanel brackets illustrated in FIGS. 9A-9G, on panel 210 a for example.

In addition to positioning solar panels 130 and attaching them to beams115, panel brackets 125 as described herein also better distribute theload from solar panels 130 along beams 115 than would be the case if thesolar panels were attached directly to beams 115. The ability of asingle panel bracket 125 to position and attach corners of up to foursolar panels to solar panel rack 100 may reduce part counts and labor,and thus cost.

Although panel brackets 125 are shown has having particular numbers ofpositioning and clinching tabs, any suitable number of such tabs may beused.

The predefined bend lines in the sheet metal blank for panel bracket 125may comprise any suitable bend-inducing features as described herein,known in the art, or later developed. The sheet metal blank for panelbracket 125 may be formed, for example, from galvanized steel sheethaving a thickness, for example, of about 1.5 millimeters. Any othersuitable material and thickness may also be used. Bend lines between toppanel 210 a and side panels 210 b may preferably be predefined, forexample, by bend-inducing features disclosed in US Patent ApplicationPublication No. 2010/0122563.

Although the illustrated examples of solar panel rack 100 are describedabove as configured for ground mounting, solar panel rack 100 mayalternatively be mounted on roof-tops. Variations of solar panel rack100 to be roof-top mounted may use vertical supports 105 as describedabove, or substitute any suitable vertical support. Any suitable methodof attaching solar panel rack 100 to a roof-top may be used.

As illustrated, transverse support 110 in solar panel rack 100 isstatically mounted to vertical supports 105 so that solar panel rack 100maintains a fixed orientation. In other variations, transverse support110 may be pivotably mounted to vertical supports 105, by any suitablepivot mechanism, to rotate around an axis extending parallel to the longaxes of hollow beams 115. This arrangement allows transverse support 110and beams 115 to be rotated so that solar panels 130 track motion of thesun across the sky during, for example, the course of a day or thecourse of a year. Any suitable rotation drive may be used to rotate theupper portion of such a solar panel rack 100 in this manner.

Although solar panel rack 100 is described above as supportingphotovoltaic solar panels, in other variations the solar panel racksdescribed herein may be used to support solar water heating panelsrather than, or in addition to, photovoltaic solar panels. Any suitablemodification may be made to the solar panel racks described herein toaccommodate mounting such solar water heating panels.

Further, although the rack structures disclosed herein have beendescribed as supporting solar panels, they may instead be used tosupport reflectors such as mirrors, for example, used to direct solarradiation to a solar energy receiver, for example. Such rack structuressupporting reflectors may be statically mounted, or pivotably mounted asdescribed above so that the reflectors may be rotated about an axis totrack motion of the sun.

The hollow beams, beam brackets, and hollow beam splices described aboveare not restricted to use in solar panel racks but may instead be usedindividually or in any combination with each other in any structure forwhich they are suitable. Further, the cross-sectional shapes of hollowbeams, beam brackets, and splices as disclosed herein are not restrictedto the particular quadrilateral cross-sectional shapes shown in thedrawings, but instead may take any shape suitable for the purpose forwhich the beams, beam brackets, or splices are employed. The hollow beamsplices described herein are not restricted to use in coupling hollowbeams formed from folded sheet metal, but may instead be used to couplehollow beams, tubes, or pipes formed by any method including cast,extruded, or machined hollow beams. Generally, the cross-sectional shapeof the splice in its expanded form should conform to and tightly fit aninner cross-sectional shape of the hollow beams, pipes, or tubes to becoupled. Similarly, the cross-sectional shape of a beam bracket shouldconform to and tightly fit an outer cross-sectional shape of the hollowbeam that it is supporting.

This disclosure is illustrative and not limiting. Further modificationswill be apparent to one skilled in the art in light of this disclosureand are intended to fall within the scope of the appended claims.

What is claimed is:
 1. A solar panel rack comprising: at least first andsecond hollow sheet metal beams arranged side by side and in parallelwith each other to define a plane, each hollow sheet metal beam having aclosed configuration of side walls along its longitudinal axis defininga hollow cross-section perpendicular to its longitudinal axis; atransverse support comprising two or more notches located in its upperedge; two or more first sheet metal brackets, each first sheet metalbracket having an outer cross-sectional shape substantially conformingto an inner cross-sectional shape of a corresponding notch in thetransverse support, having an inner cross-sectional shape substantiallyconforming to the outer-cross sectional shape of a corresponding hollowsheet metal beam, positioned in the corresponding notch in thetransverse support, and attached to and supporting the correspondinghollow sheet metal beam at least partially within the correspondingnotch in the transverse support, each first sheet metal bracket formedfrom a single sheet of metal; and one or more second sheet metalbrackets, each second sheet metal bracket comprising a top panel andoppositely positioned side panels bent downwards from the top panel toform an inner cross-sectional shape conforming to the outercross-sectional shape of a corresponding hollow sheet metal beam,positioned on and attached to the corresponding hollow sheet metal beam,and comprising one or more upwardly pointing clinching tabs and one ormore upwardly pointing protrusions, each second sheet metal bracketformed from a single sheet of metal; wherein the clinching tabs areconfigured to be clinched to features on a solar panel or solar panelassembly to attach the solar panel or solar panel assembly to the solarpanel rack in a desired location in a plane defined by the solar panelrack, and the protrusions are configured to facilitate electricalcontact between the second sheet metal brackets and the solar panel orsolar panel assembly when the features on the solar panel or solar panelassembly are clinched by the clinching tabs; wherein each second sheetmetal bracket is configured to position and attach adjacent corners offour solar panels or solar panel assemblies to the solar panel rack. 2.The solar panel rack of claim 1, wherein the features on the solar panelor solar panel assembly are sandwiched between the protrusions and theclinching tabs when the clinching tabs are clinched.
 3. The solar panelrack of claim 1, wherein the upwardly pointing protrusions areconfigured to pierce an insulating coating on the features on the solarpanel or solar panel assembly when the features are clinched by theclinching tabs.
 4. The solar panel rack of claim 1, wherein the upwardlypointing protrusions comprise sharp edges.
 5. The solar panel rack ofclaim 1, wherein the upwardly pointing protrusions comprise sharppoints.
 6. The solar panel rack of claim 1, wherein the upwardlypointing protrusions have a conical volcano shape.
 7. The solar panelrack of claim 1, wherein each second sheet metal bracket comprises oneor more upwardly pointing positioning tabs configured to contactfeatures on the solar panel or solar panel assembly to position thesolar panel or solar panel assembly in the desired location.
 8. Thesolar panel rack of claim 7, wherein the positioning tabs of each secondsheet metal bracket are located in a square or rectangular arrangementin a central portion of a top surface of the second sheet metal bracketand extend upward from the top surface.
 9. The solar panel rack of claim1, wherein the electrical contact facilitated by the protrusions formspart of an electrical path from the solar panel or solar panelassemblies through the one or more second sheet metal brackets and theunderlying support structure to ground.
 10. The solar panel rack ofclaim 1, wherein each second sheet metal bracket comprises one or moretabs configured to engage corresponding slots or other openings in acorresponding hollow sheet metal beam to attach the sheet metal bracketto the hollow sheet metal beam, and one or more downwardly pointingprotrusions configured to flex an upper panel of the hollow sheet metalbeam to provide an elastic restoring force securing the tabs in theslots or other openings.
 11. The solar panel rack of claim 1, whereineach first sheet metal bracket comprises upper flanges configured to beclosed around the corresponding hollow sheet metal beam to capture thehollow sheet metal beam within the first sheet metal bracket.
 12. Thesolar panel rack of claim 1, wherein each hollow sheet metal beam isformed by bending a single sheet metal blank comprising preformed tabsand slots configured to secure the sheet metal blank in a beamconfiguration upon bending of the blank into the beam configuration. 13.The solar panel rack of claim 1, wherein each hollow sheet metal beam isformed from a single sheet of metal and comprises preformed slots orother openings configured to predefine the locations at which solarpanels or solar panel assemblies are to be attached to the solar panelrack.
 14. The solar panel rack of claim 1, wherein the transversesupport is formed from a single sheet of metal and comprises flangesforming side walls for the notches, and the side walls of each notch areattached to opposite sides of a first sheet metal bracket positioned inthe notch.
 15. The solar panel rack of claim 14, wherein the transversesupport comprises one or more preformed tabs or slots configured toengage one or more corresponding slots or tabs in the first sheet metalbracket to at least partially secure the first sheet metal bracket inposition on the transverse support.
 16. The solar panel rack of claim 1,wherein each first sheet metal bracket comprises one or more tabs orslots configured to engage one or more corresponding slots or tabs inthe transverse support to at least partially secure the first sheetmetal bracket in position on the transverse support.
 17. The solar panelrack of claim 1, wherein each first sheet metal bracket extends beyondthe transverse support in both directions along its corresponding hollowsheet metal beam.
 18. The solar panel rack of claim 1, comprising: athird hollow sheet metal beam arranged collinearly with the first or thesecond hollow sheet metal beam and having a closed configuration of sidewalls along its longitudinal axis defining a hollow cross-sectionperpendicular to its longitudinal axis; and an expandable andcollapsible hollow sheet metal beam having a closed configuration ofside walls along its longitudinal axis defining a hollow cross-sectionperpendicular to its longitudinal axis, the expandable and collapsiblehollow sheet metal beam configured to be bent along predefined bendlines to assume a collapsed configuration, inserted while in thecollapsed configuration into adjoining ends of the collinear hollowsheet metal beams, expanded to a configuration having an outercross-sectional shape conforming to and tightly fitting an internalcross-sectional shape of the collinear hollow sheet metal beams, thenattached to both of the collinear hollow sheet metal beams to couple thecollinear hollow sheet metal beams to each other.
 19. The solar panelrack of claim 1, wherein: each second sheet metal bracket comprises oneor more upwardly pointing positioning tabs configured to contactfeatures on the solar panel or solar panel assembly to position thesolar panel or solar panel assembly in the desired location; each secondsheet metal bracket comprises one or more tabs configured to engagecorresponding slots or other openings in a corresponding hollow sheetmetal beam to attach the sheet metal bracket to the hollow sheet metalbeam, and one or more downwardly pointing protrusions configured to flexan upper panel of the hollow sheet metal beam to provide an elasticrestoring force securing the tabs in the slots or other openings; andthe upwardly pointing protrusion comprise sharp edges or sharp points.20. A solar panel rack comprising: at least first and second hollowsheet metal beams arranged side by side and in parallel with each otherto define a plane, each hollow sheet metal beam having a closedconfiguration of side walls along its longitudinal axis defining ahollow cross-section perpendicular to its longitudinal axis; atransverse support comprising two or more notches located in its upperedge; two or more first sheet metal brackets, each first sheet metalbracket having an outer cross-sectional shape substantially conformingto an inner cross-sectional shape of a corresponding notch in thetransverse support, having an inner cross-sectional shape substantiallyconforming to the outer-cross sectional shape of a corresponding hollowsheet metal beam, positioned in the corresponding notch in thetransverse support, and attached to and supporting the correspondinghollow sheet metal beam at least partially within the correspondingnotch in the transverse support, each first sheet metal bracket formedfrom a single sheet of metal; and one or more second sheet metalbrackets, each second sheet metal bracket comprising a top panel andoppositely positioned side panels bent downwards from the top panel toform an inner cross-sectional shape conforming to the outercross-sectional shape of a corresponding hollow sheet metal beam,positioned on and attached to the corresponding hollow sheet metal beam,and comprising one or more upwardly pointing clinching tabs and one ormore upwardly pointing protrusions, each second sheet metal bracketformed from a single sheet of metal; wherein the clinching tabs areconfigured to be clinched to features on a solar panel or solar panelassembly to attach the solar panel or solar panel assembly to the solarpanel rack in a desired location in a plane defined by the solar panelrack, and the protrusions are configured to facilitate electricalcontact between the second sheet metal brackets and the solar panel orsolar panel assembly when the features on the solar panel or solar panelassembly are clinched by the clinching tabs; and wherein each secondsheet metal bracket comprises one or more tabs configured to engagecorresponding slots or other openings in a corresponding hollow sheetmetal beam to attach the sheet metal bracket to the hollow sheet metalbeam, and one or more downwardly pointing protrusions configured to flexan upper panel of the hollow sheet metal beam to provide an elasticrestoring force securing the tabs in the slots or other openings.
 21. Asolar panel rack comprising: at least first and second hollow sheetmetal beams arranged side by side and in parallel with each other todefine a plane, each hollow sheet metal beam having a closedconfiguration of side walls along its longitudinal axis defining ahollow cross-section perpendicular to its longitudinal axis; atransverse support comprising two or more notches located in its upperedge; two or more first sheet metal brackets, each first sheet metalbracket having an outer cross-sectional shape substantially conformingto an inner cross-sectional shape of a corresponding notch in thetransverse support, having an inner cross-sectional shape substantiallyconforming to the outer-cross sectional shape of a corresponding hollowsheet metal beam, positioned in the corresponding notch in thetransverse support, and attached to and supporting the correspondinghollow sheet metal beam at least partially within the correspondingnotch in the transverse support, each first sheet metal bracket formedfrom a single sheet of metal; one or more second sheet metal brackets,each second sheet metal bracket comprising a top panel and oppositelypositioned side panels bent downwards from the top panel to form aninner cross-sectional shape conforming to the outer cross-sectionalshape of a corresponding hollow sheet metal beam, positioned on andattached to the corresponding hollow sheet metal beam, and comprisingone or more upwardly pointing clinching tabs and one or more upwardlypointing protrusions, each second sheet metal bracket formed from asingle sheet of metal; a third hollow sheet metal beam arrangedcollinearly with the first or the second hollow sheet metal beam andhaving a closed configuration of side walls along its longitudinal axisdefining a hollow cross-section perpendicular to its longitudinal axis;and an expandable and collapsible hollow sheet metal beam having aclosed configuration of side walls along its longitudinal axis defininga hollow cross-section perpendicular to its longitudinal axis, theexpandable and collapsible hollow sheet metal beam configured to be bentalong predefined bend lines to assume a collapsed configuration,inserted while in the collapsed configuration into adjoining ends of thecollinear hollow sheet metal beams, expanded to a configuration havingan outer cross-sectional shape conforming to and tightly fitting aninternal cross-sectional shape of the collinear hollow sheet metalbeams, then attached to both of the collinear hollow sheet metal beamsto couple the collinear hollow sheet metal beams to each other; whereinthe clinching tabs are configured to be clinched to features on a solarpanel or solar panel assembly to attach the solar panel or solar panelassembly to the solar panel rack in a desired location in a planedefined by the solar panel rack, and the protrusions are configured tofacilitate electrical contact between the second sheet metal bracketsand the solar panel or solar panel assembly when the features on thesolar panel or solar panel assembly are clinched by the clinching tabs.22. A solar panel rack comprising: at least first and second hollowsheet metal beams arranged side by side and in parallel with each otherto define a plane, each hollow sheet metal beam having a closedconfiguration of side walls along its longitudinal axis defining ahollow cross-section perpendicular to its longitudinal axis; atransverse support comprising two or more notches located in its upperedge; two or more first sheet metal brackets, each first sheet metalbracket having an outer cross-sectional shape substantially conformingto an inner cross-sectional shape of a corresponding notch in thetransverse support, having an inner cross-sectional shape substantiallyconforming to the outer-cross sectional shape of a corresponding hollowsheet metal beam, positioned in the corresponding notch in thetransverse support, and attached to and supporting the correspondinghollow sheet metal beam at least partially within the correspondingnotch in the transverse support, each first sheet metal bracket formedfrom a single sheet of metal; and one or more second sheet metalbrackets, each second sheet metal bracket comprising a top panel andoppositely positioned side panels bent downwards from the top panel toform an inner cross-sectional shape conforming to the outercross-sectional shape of a corresponding hollow sheet metal beam,positioned on and attached to the corresponding hollow sheet metal beam,and comprising one or more upwardly pointing clinching tabs and one ormore upwardly pointing protrusions, each second sheet metal bracketformed from a single sheet of metal; wherein the clinching tabs areconfigured to be clinched to features on a solar panel or solar panelassembly to attach the solar panel or solar panel assembly to the solarpanel rack in a desired location in a plane defined by the solar panelrack, and the protrusions are configured to facilitate electricalcontact between the second sheet metal brackets and the solar panel orsolar panel assembly when the features on the solar panel or solar panelassembly are clinched by the clinching tabs; wherein each second sheetmetal bracket comprises one or more upwardly pointing positioning tabsconfigured to contact features on the solar panel or solar panelassembly to position the solar panel or solar panel assembly in thedesired location; wherein each second sheet metal bracket comprises oneor more tabs configured to engage corresponding slots or other openingsin a corresponding hollow sheet metal beam to attach the sheet metalbracket to the hollow sheet metal beam, and one or more downwardlypointing protrusions configured to flex an upper panel of the hollowsheet metal beam to provide an elastic restoring force securing the tabsin the slots or other openings; and wherein the upwardly pointingprotrusion comprise sharp edges or sharp points.